user/polybar: add 1px scrollbar

apparently the startup script used to always start a non-existent bottom
bar... whoops

modules/user/polybar.nix

@@ -12,6 +12,21 @@
     enable = true;
     script = builtins.readFile ../../scripts/polybar.sh;
     settings = {
+      "bar/scroller" = {
+        monitor = "eDP-1";
+        width = "100%";
+        height = 1;
+        background = colours.background1;
+        spacing = 2;
+        override-redirect = true;
+
+        modules.center = "workspaces-stub";
+        scroll = {
+          up = "#workspaces-stub.prev";
+          down = "#workspaces-stub.next";
+        };
+      };
+
       "bar/top" = {
         monitor = "eDP-1";
         width = "100%";
@@ -111,6 +126,22 @@
         };
       };
 
+      "module/workspaces-stub" = {
+        type = "internal/bspwm";
+        pin-workspaces = true;
+        enable-click = false;
+        enable-scroll = false;
+        reverse-scroll = false;
+        label = {
+          monitor = "";
+          focused = "";
+          occupied = "";
+          empty = "";
+          urgent = "";
+          separator = "";
+        };
+      };
+
       "module/title" = {
         type = "internal/xwindow";
         format = {

scripts/polybar.sh

@@ -1,4 +1,4 @@
 #!/bin/sh
 
-polybar top    >>/tmp/bar-top.log 2>&1 &
-polybar bottom >>/tmp/bar-bottom.log 2>&1 &
+polybar top      >> ${XDG_RUNTIME_DIR}/bar-top.log 2>&1 &
+polybar scroller >> ${XDG_RUNTIME_DIR}/bar-scroller.log 2>&1 &